בֵּאדַ֛יִן דָּרְיָ֥וֶשׁ מַלְכָּ֖א שָׂ֣ם טְעֵ֑ם וּבַקַּ֣רוּ ׀ בְּבֵ֣ית סִפְרַיָּ֗א דִּ֧י גִנְזַיָּ֛א מְהַחֲתִ֥ין תַּמָּ֖ה בְּבָבֶֽל׃
Then Darius the king made a decree, and search was made in the house of the archives, where the treasures were laid up, in Babylon.
Rashi on Ezra
and they searched They searched in the library where the archives were stored in Babylon.